Inhibitors of proteolytic enzymes have multiple roles in limiting the causes of inflammation, which if not controlled, would result in acute and chronic tissue damage. Human neutrophil elastase (HNE) and other neutrophil proteases are controlled by plasma proteins belonging to the serine protease inhibitor (serpin) family. Inactivation or insufficient production of serpins can result in life-threatening diseases. Lexin has constructed a novel serpin (LEX032) with the ability to inhibit HNE, cathepsin G and chymotrypsin. LEX032 has been shown to be an efficacious inhibitor of neutrophil recruitment. The data obtained from the study of LEX032, e.g., high resolution crystal structure and a general kinetic scheme of serpin/enzyme reactions, was used to guide the design and construction of several novel variants of human serpins. Since these proteins are being produced in E. coli they are, unlike their wild-type counterparts, non-glycosylated. The purpose of this project is to determine if the pharmacokinetic and biodistribution patterns of several recombinant serpins, especially those which are non-glycosylated, are consistent with the patterns needed for efficacious drugs and to obtain data to guide the design of dosing regimes to be used in both preclinical (efficacy and toxicity) and clinical studies. This is a critical step on the path to determine the feasibility of using human recombinant serpins for the treatment of disease. In phase two, the data obtained will be applied to the toxicity and clinical evaluation of serpins with potential as drugs for the treatment of the destructive inflammatory processes in pulmonary inflammation, acute pancreatitis, reperfusion injury and other neutrophil related disorders. PROPOSED COMMERCIAL APPLICATION: Novel recombinant inhibitors of human neutrophil serine proteases have the potential of treating several forms of acute inflammation, including many which today are not treatable. These diseases include acute pancreatitis, acute pulmonary inflammation and reperfusion injury. The potential market represents several hundreds of thousand of patients in the U. S. Grant support would allow more rapid evaluation of drug candidates and commercialization of the most promising candidates. Success at this stage will greatly increase the probability of commercial success of the company.